Visual Diagnosis

Presentation

An 11½-year-old girl presents to the clinic with a 6-week history of left leg pain. She is an active participant in gymnastics, and, although she has fallen a few times during practice, she denies any significant trauma. Recently, she has limited her participation in training because her leg pain has increased significantly. However, the pain does not restrict her walking. She denies other limb or joint pain, night sweats, joint swelling, fever, rash, anorexia, weight loss, or recent illness. Her past medical history is unremarkable.

The patient is a well-appearing girl. Vital signs are normal. The only significant finding upon physical examination is point tenderness over the anterior aspect of the proximal left tibia. There is no swelling, warmth, or erythema of the left leg or knee. There is no active or passive restriction of range of motion of all joints. The remainder of the physical examination is normal. Laboratory examination reveals a normal complete blood cell count and erythrocyte sedimentation rate and normal levels of C-reactive protein, electrolytes, blood urea nitrogen, creatinine, and liver enzymes. Urinalysis yields unremarkable results.

Radiography of the left leg reveals an abnormality that may be associated with her pain (Fig 1).

Diagnosis: Bone Cyst of Proximal Tibia

Radiography reveals a radiolucent oval lesion; it is most likely a unicameral bone cyst (UBC). There is no evidence of a fracture. The patient is referred to a pediatric orthopedist for further evaluation.